1. Technical Field
Embodiments of the present invention generally relates to an electrophotographic image forming apparatus such as a copier, a facsimile machine, a printer, or a multifunction peripheral (MFP, i.e., a multifunction machine) having at least two of copying, printing, facsimile transmission, plotting, and scanning capabilities and, more particularly, to an image forming apparatus including multiple developing devices.
2. Description of the Related Art
In typical tandem image forming apparatuses such as copiers, facsimile machines, printers, and MFPs, multiple developing devices corresponding to different colors (e.g., black, yellow, magenta, and cyan) are arranged to face an intermediate transfer belt. There are developing devices that employ two-component developer including toner and carrier to develop latent images on image bearers such as photoconductor drums. Toner and carrier are may be supplied from separate containers. Alternatively, toner and carrier are premixed and contained in a common container.
Premix developing, in which degraded carrier is discharged from the developing device, is advantageous in that speed of degradation of carrier in the developing device is retarded, and replacement cycle of developer is elongated.